fuel tank plumbing

C. G. Taylor, also the designer of the Cub, must have been thinking
about
those steep climbs in a Taylorcraft when he designed the ram-air
tubes on
the wing tanks because they are bent more than 90 degrees downward so
they
face directly into the slipstream during a steep climb.

The down angle is to keep rain out. The airflow will be parallel
to the top of the wing in any attitude except full stall.

On the subject of a small header tank in addition to a fuselage tank,
that
sure does sound a little like Rube Goldberg to me. It must a device
to cure
a history of fuel starvation, something I have never heard of in a
simple
system like the Taylorcraft's. OTOH,maybe there's a good reason for
it.

Some airplanes had tiny header tanks to increase usable fuel.
In a slip or steep nose-down glide (especially with flaps on some
aircraft) the fuel moves away from the tank outlet and the engine might
starve if the tanks are low. The small header is intended to keep the
engine supplied while in that attitude. The Glastar had a retrofit kit
of two small headers to overcome the starvation problem, since the very
effective flaps resluted in a rather large unusable fuel quantity,
limiting range.
Other airplanes use two tank outlets, one front and another
rear, plumbed together. Citabria is a good example.

Dan

On Tue, 25 Jan 2005 12:16:41 -0500, Corky Scott
wrote:

On Tue, 25 Jan 2005 08:13:09 -0800, Ed Sullivan
wrote:

I'm not sure why you have a header tank unless it is for inverted
flight. On my Jungster the wing tank feeds into the fuel valve as does
the fuselage tank. I can then select either the wing or fuselage tank,
but not both otherwise the wing tank could overflow the fuselage tank.
I have both upright and inverted vents on the fuselage tank and
inverted tank. On the wing tank I just use a vented cap.

Ed Sullivan

Really? You can't just plumb the wing tanks into the header tank?
Thought that was done all the time. Is it necessary to vent the
header tank if the wing tanks are properly vented?

Thanks, Corky Scott

Corky, I don't know why you need a header tank with a fuselage tank. I
have an inverted tank at the bottom of my fuselage tank which is
separate from the main tank, but has a 1" tube running to the bottom
of it to feed the inverted tank. Both it and the main tank are vented
for upright flight and a second vent runs from the inverted tank for
inverted flight. The fuel is fed to the fuel valve through an
aerobatic flop tube. When I am on the wing tank I switch the valve and
the fuel gavity feeds to the gascolator. I haven't looked at it in a
long time, but the location of the vents is pretty critical.

Ed Sullivan

So far, I am down to two concepts:

1) feed header tank from either main fuselage tank or upper wing tank with a
main/aux selector valve

2) feed header tank from only the main fuselage tank; fill main fuselage
tank (only until sight gauge shows full) from the upper wing tank via a
shutoff valve

Any other suggestions? (keep 'em simple)

Monty

On Tue, 25 Jan 2005 19:25:52 -0600, "pwm" wrote:

So far, I am down to two concepts:

1) feed header tank from either main fuselage tank or upper wing tank with a
main/aux selector valve

2) feed header tank from only the main fuselage tank; fill main fuselage
tank (only until sight gauge shows full) from the upper wing tank via a
shutoff valve

Any other suggestions? (keep 'em simple)

Monty


The simplest is to plumb the wing tank through the aux side of the
fuel selector valve directly to the gascolator and use a vented cap.
You haven't really given enough detail about how your main and header
tanks are set up and connected. Will you have a fuel pump or is
everything gravity feed?

Ed

On Tue, 25 Jan 2005 16:25:13 -0800, Ed Sullivan
wrote:

Corky, I don't know why you need a header tank with a fuselage tank.

Sorry, this was a part of the post I missed. I did not realise that
was the situation.

I was thinking purely about wing mounted tanks plumbed into a header
tank.

Corky Scott